This note reports preliminary results of a comparative transaction log analysis study of user searching in two digital libraries in the United States — a large-scale digital library in the domain of US history and a domain-independent federal-level digital library that aggregates digital collections regardless of their subject scope. This investigation reveals similarities in user search behavior among the two types of digital libraries with regard to rate of collection-level search use and application of search limits, most often occurring search categories, etc. At the same time, notable differences are observed in the rate of fielded search and phrase search use, average search query length and frequencies, and distribution of some search categories. This study provides empirical data to support digital library developers’ decision making regarding audience-based information organization in large-scale digital libraries.